When you fill the gas tank to full on my sons sportsman 90 , it leaks alot of fuel for an overflow/vent line located near the top of the fuel tank . The line that I am referring to comes out of the gas tank , splits to a tee ,one side of the tee goes to the petcock valve , the other is just routed down the front of the frame . I just picked the bick up from the dealer , having it serviced .